Ryan takes 12 minutes to rake up and bag a pile of leaves. His sister Kareesa takes twice as long. How many minutes would it take both of them working together to complete 10 bags of leaves

Answer 1

Ryan's rate per bag = 1/12
sister's rate ber bag = 1/24
combined rate = 1/12 + 1/24 = 3/24
time per bag working together = 1/(3/24) = 24/3 = 8 minutes

so it would take them 80 minutes to do 10 bags